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View Full Version : Howto use a speaker with BS2 Hmwk board???



logan996
03-06-2010, 06:58 AM
Hey i have a basic stamp Hmwk board and a old speaker, i was wondering can i use it useing some aligator clips and jumper wires but without any outside things to buy? and if so could someone post a quick simple bit of code for me to see and how id wire it up?

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"When the government is afraid of the people there is liberty, when the people are afraid of the government, there is tryanny"

Thomas Jefferson

Mike Green
03-06-2010, 07:37 AM
You'll probably be able to make a little noise with the speaker, but the Stamp can't provide enough power for much sound. For that you'll need some kind of amplifier, even something as simple as a switching transistor. Download and read the "BASIC Stamp Syntax and Reference Manual", specifically the chapter on the FREQOUT statement.

The Homework Board has built-in 220 Ohm resistors in series with the I/O pins. These will prevent any possible damage from a direct connection of a speaker between the I/O pin and either ground or +5V, but will also reduce the amount of power available for the speaker.

logan996
03-06-2010, 09:20 AM
ok thanks!

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"When the government is afraid of the people there is liberty, when the people are afraid of the government, there is tryanny"

Thomas Jefferson

Peter W5HZA
03-07-2010, 07:47 AM
Hi, I'm Slightly hard-of-hearing (71 years old) and I found I could not hear from the Piezo speaker. So... i ordered a "Crystal Earplug" from Midnightscience.com and bridged a 10 Megaohm resistor across the crystal earplug, connecting it to the BS2 Stamp. Note: This device is an extremely high impedance device so it does not load the stamp and no polarity is necessary to heed. The sound is so loud, you just leave the earplug rest on the desk. No amplifier was necessary and, the earplug inscreased the sound by 9.4 DB which is approximately 8 times louder than with the Piezo speaker. Check out this website and for a couple of bucks, you'll be quite surprised how strong the sound is coming out of the earplug!

logan996
03-07-2010, 09:10 AM
cool, but exactly how much? and what was the shipping? and well how big is it in comparison? (sorry for all the questions)

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"When the government is afraid of the people there is liberty, when the people are afraid of the government, there is tryanny"

Thomas Jefferson

Peter W5HZA
03-07-2010, 10:32 AM
Well, I purchased the package of three (3) each of the Crystal Earphones from midnightscience.com for less than 8 or 9 dollars. However, you can purchase only one for much less. Don't remenber a shipping charge as this is so small an item, it was shipped U. S. mail. Size wise? It is nothing more than an Earplug like that found with any portable audio player etc., very small. But, the volume is so intense, you DO NOT NEED to plug it into you ear when using with the BS2 Stamp FREQOUT, DTMF, or any other sound command. Click on midnight.com and check their price on this item. Good luck !

logan996
03-07-2010, 11:23 AM
ok thanks! :D

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"When the government is afraid of the people there is liberty, when the people are afraid of the government, there is tryanny"

Thomas Jefferson

Peter W5HZA
03-07-2010, 09:17 PM
Sorry... The complete website is: midnightscience.com...Try it!

logan996
03-07-2010, 09:35 PM
ok ty!

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"When the government is afraid of the people there is liberty, when the people are afraid of the government, there is tryanny"

Thomas Jefferson

PJ Allen
03-07-2010, 10:09 PM
I bet you can still get a crystal earphone like this at Radio Shack.